This proposal requests funds for the purchase of a JEOL JSM-6400 Scanning Electron Microscope (SEM) and JUS-ARC64 Digital Image Archive System for the JSM 6400 series of SEMs for the Integrated Microscopic Analysis Facility (IMAF) in the University of South Carolina School of Medicine. This instrument will serve as the principal SEM for 7 NIH funded investigators for analysis of a wide variety of experimental systems. These investigations will encompass experiments ranging from general morphology to the localization and analysis of specific macromolecules on the surface of a variety of cells. The JEOL 6400 SEM will replace the existing JEOL-35U, which is a 18 year old instrument. The JSM-35U has experienced an increasing number of maintenance problems and currently, with its extensive down time, is not a reliable research or training instrument. Among the major problems with the JSM-35U is a chronic, incurable problem which limits resolution and use of the viewing CRT for photography to the upper two thirds of the screen. At this time resolution in the JSM-35 is approximately 50nm which limits the instrument to low magnification work. The JSM-35U also does not have either the capability or stability to resolve backscattered electrons for detection of gold used in immunolocalization of surface proteins, and does not interface with the extensive digital imaging capabilities which exist in the IMAF. The JEOL 6400 SEM, which represents state-of-the-art technology for scanning electron microscopes, will provide the capability to do high resolution scanning electron microscopy, to detect backscattered electrons, and to interface the existing image analysis equipment. These capabilities are essential to the continued development of the research programs of the 7 NIH funded researchers in this grant.